In our daily lives, such electronic display devices as mobile phones and tablet computers have become indispensable devices for communication and entertainment. However, the capacity for a local cell of the electronic display device is limited. When the electronic display device has been used for a period of time, the cell power may be lowered to a level insufficient to operate the display device. For example, when the cell power for a mobile phone is insufficient, it is unable to make an emergency call. At this time, when a user is in the open air or at any other place where no electric supply is available, it is impossible to charge the local cell in time.
Thus, a new display device is desiderated, so as to overcome the above-mentioned drawback.